A nitride semiconductor light emitting device may have a light emitting region containing infrared, blue, and green regions. An example of a nitride semiconductor light emitting device is a GaN-based nitride semiconductor light emitting device.
A GaN-based nitride semiconductor light emitting device is formed with a buffer layer on a sapphire substrate, and an n-GaN layer and a p-GaN layer are formed on the buffer layer.
An electrode layer is formed on the n-GaN layer and the p-GaN layer. In operation, a voltage is applied thereto so that light is generated from the active layer.
In a nitride semiconductor light emitting device, because the sapphire substrate and the n-GaN layer have different lattice constants, dislocation of the boundary surfaces of the sapphire substrate and the n-GaN layer occurs.
In order to reduce the difference of the lattice constants between the sapphire substrate and the n-GaN layer, a buffer layer is formed on the sapphire substrate.
However, even when the n-GaN layer is formed on the buffer layer, there is a limit to the amount by which dislocation spreading to the n-GaN layer can be reduced.